Sanitation in food preparation is usually principally for the direct benefit of the consumer, but where the food is produced by a living animal, as in the instance of milk, it is also desirable to safeguard the animal--as well as the product--by taking suitable sanitary precautions. The udder and particularly the teats of milk animals are highly susceptible to infection from contact with flies, manure, people's hands, etc. Hence, good milking technique includes assured application of suitable disinfecting composition.
For many years the preferred germicide in disinfectants for such use has been iodine, which in elemental form is not soluble in water (though some of its salts and other combined forms are) but is soluble in alcohol and many other organic liquids. Its traditional popularity stems in part from the characteristically intransigent stain it leaves as visible evidence of its application. However, it and its customary liquid formulations foster chapping and cracking, which not only are painful but also provide new sites for infection.
Iodophoric compositions advanced as less troublesome are found in these representative U.S. Pat. Nos.: Hall 3,663,694 (ethoxylated lanolin), Eckols 4,012,504 (mineral oil, with polyoxyethylene cetyl ether), Foll et al. 4,288,428 (alkylphenoxypoly[ethyleneoxy]ethanol or polyvinylpyrrolidone), Lauermann et al. 4,466,959 (glycerin, paraffin oil, and higher fatty acids), and Witkin (povidone-iodine complex plus hydrogen peroxide). Such efforts suggest that there is a need for further improvements in this art, preferably a new departure rather than simply more--or more varied--iodophors.
Other germicides have been made the basis of disinfectants for udder treatment. The efficacy of chlorine-containing compositions, specifically hypochlorites ("Clorox") is reported in Journal of Dairy Science, vol. 56, no. 1, p. 148 (Jan. 1973) and references cited therein. However, though efficacious, they have not been generally accepted, in part because of tradition, and in part for lack of coloring or equivalent identifiability so as to enable positive monitoring that the treatment has actually been accomplished.
Lasting colorizers of hypochlorite bleaches used for different purposes also are identified in such U.S. Pat. Nos. as Kitchen et al. 3,544,373 (phthalocyanines), Hung 4,536,367 (triphenylmethanes), and Sudbury 4,457,855 (anthraquinones), for example. However, they are not suitable for the present purpose because of their persistence.
Prince U.S. Pat. No. 3,950,554, while urging the use of a fatty acid ester plus drying oil to form a water-resistant film on udders, included a suggestion of an edible organic dye, such as carotene, as well as hypochlorites, iodophors, and/or other udder disinfectants. His teachings failed to make any appreciable impression on the art, at least in the direction suggested above as being desirable here.
My aforementioned contribution to this art provided a two-step post-milking and pre-milking method of udder care, including steps of applying an iodine-free colorizing liquid thereto after milking, then decolorizing the udder by another liquid application before the next milking. Such practice is still effective and appropriate, but it may be modified and simplified under appropriate circumstances.